NASA mission prepares to crash into an asteroid

A NASA spacecraft that will deliberately collide with an asteroid is approaching its target.

The DART, or Double Asteroid Redirection Test, mission will have an encounter with the space rock on September 26, after launching 10 months ago.

The spacecraft will crash into an asteroid’s moon to see how it affects motion in space. A live stream of images captured by the spacecraft will be available on the NASA website starting at 6:30 pm.The impact should occur around 20:14.

The mission is heading to Dimorphos, a small moon orbiting the asteroid Didymos.

The asteroid system poses no threat to Earth, NASA officials said, making it a perfect target for testing a kinetic impact.

The event will be the agency’s first large-scale demonstration of deflection technology that can protect the planet. “For the first time, we are going to measurably change the orbit of a celestial body in the universe,” said Robert Braun, head of the Space Exploration Sector at the Johns Hopkins University Applied Physics Laboratory.

Near-Earth objects are asteroids and comets with orbits that place them 48.3 million kilometers from Earth. Detecting the threat of near-Earth objects, which can cause serious damage, is a primary focus for NASA and other space organizations around the world.

What will the impact of the collision with the asteroid be like?

Astronomers discovered Didymos more than two decades ago. It is almost 0.8 kilometers in diameter.

Meanwhile, Dimorphos is 160 meters in diameter and its name means “two forms”. The spacecraft recently caught the first glimpse of Didymos using an instrument called the Didymos Reconnaissance and Asteroid Camera for Optical Navigation, or DRACO.

It was about 20 million miles away from the binary asteroid system when it took the images in July.

On the day of impact, the images taken by DRACO will not only reveal our first look at Dimorphos, but the spacecraft will use them to autonomously guide itself to an encounter with the tiny moon.

During the event, these images will be transmitted back to Earth at a rate of one per second, providing a “pretty impressive” view of the moon, said Nancy Chabot, planetary scientist and DART coordinating lead at the Applied Physics Laboratory.

At the time of impact, Didymos and Dimorphos will be relatively close to Earth – within 6.8 million miles (11 million kilometers). The spacecraft will accelerate to around 15,000 miles per hour (24,140 kilometers per hour) when it collides with Dimorphos.

The collision will be recorded by the LICIACube, or Light Italian CubeSat for Imaging of Asteroids, a companion cube satellite provided by the Italian Space Agency. The briefcase-sized CubeSat hitched a ride with DART into space. Three minutes after impact, the CubeSat will pass through Dimorphos to capture images and videos.

The video, while not available immediately, will be broadcast back to Earth in the weeks and months after the collision.

protecting the planet

Dimorphos was chosen for this mission because its size is relative to asteroids that could pose a threat to Earth. The spacecraft is about 100 times smaller so it won’t destroy the asteroid.

The quick impact will only change the speed of Dimorphos as it orbits, by 1%, which doesn’t sound like much – but it will change the moon’s orbital period.

“Sometimes we describe it as driving a golf cart into a big pyramid or something,” Chabot said.

“But for Dimorphos, it’s really about asteroid deflection, not disruption. This will not blow up the asteroid; It won’t break you into too many pieces.”

The push will slightly change Dimorphos and make it more gravitationally bound to Didymos — so the collision doesn’t change the binary system’s path around Earth or increase its chances of becoming a threat to our planet, Chabot said.

Dimorphos completes an orbit around Didymos every 11 hours and 55 minutes. After impact, this may change to 11 hours and 45 minutes, but follow-up observations will determine how much of a change has occurred.

Astronomers will use ground-based telescopes to observe the binary asteroid system and see how much the orbital period of Dimorphos has changed, which will determine whether DART was successful. Space telescopes such as Hubble, Webb and NASA’s Lucy mission will also observe the event.

In four years, the European Space Agency’s Hera mission will arrive to study Dimorphs, measure the physical properties of the moon and observe the impact of DART and the moon’s orbit.

No asteroid is currently on a direct impact course with Earth, but there are over 27,000 near-Earth asteroids in all shapes and sizes.

The valuable data collected by DART and Hera will contribute to planetary defense strategies, especially understanding what kind of force can change the orbit of a near-Earth asteroid that could collide with our planet.